A lockdown was ordered at Penn State’s Abington campus, reports ABC Philadelphia. The threat was centered around the school’s library. Penn State Abington is located in Montgomery County, Pennsylvania. At 4:42 p.m. local time, the lockdown was lifted by authorities.

Here’s what you need to know:

1. The ‘Shotgun’ Was a BB Gun

Heavy response by Abington Twp Police at PennState Abington as report of person with gun prompts shelter in place pic.twitter.com/HLyOmfjN5f

A call was made to police at around 3:40 p.m. The caller said a man armed with a shotgun was roaming around the campus. Cops later confirmed that the “shotgun” was a BB gun. Two people have been arrested in relation to the disturbance.

5. Less Than 4,000 Students Attend the Campus

There are 3,400 students who study full-time at the school during the academic year. The Penn State Abington Wikipedia page states that the library is open to use for any resident of the commonwealth of Pennsylvania.